package web;


import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.lang.reflect.Method;


public abstract class BaseServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doPost(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setContentType("text/html; charset=UTF-8");
        req.setCharacterEncoding("UTF-8");
        String action = req.getParameter("action");

        //使用反射优化大量的if else语句
        // 使用反射执行指定的方法
        try {
            //获取action业务鉴别字符串，获取相关的业务、方法反射对象
            Method method = this.getClass().getDeclaredMethod(action, HttpServletRequest.class, HttpServletResponse.class);
            System.out.println(method);
            //调用目标业务 方法
            //这里是调用指定的方法action
            method.invoke(this, req, resp);
        } catch (Exception e) {
            e.printStackTrace();
            throw new RuntimeException(e);// 把异常抛给 Filter 过滤器
        }

    }


}
